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A customer operating in North Sea needed to remove 9 ⅝-in. 53.5-lb/ft (79.787-kg/m) casing down to 165 ft (50 m) below a well’s 13 ⅜-in. shoe. Initially the customer set out to remove the casing through conventional cut-and-pull methods. Multiple cuts in the casing were made with limited success in pulling the casing free due to barite settlement and cement between the casing strings.

Baker Hughes, a GE company (BHGE), suggested a milling operation with an 11-in. pilot mill, upgraded with METAL MUNCHER™ Advanced Milling Technology (AMT) carbides, the industry’s most durable, effective cutting and swarf control tungsten-carbide to cut or mill even the toughest steels. xSight™ smart intervention services was used to relay mechanical and dynamic readings downhole in real time. Combined, these resulted in minimized risk and increased job efficiency.

The wellbore Intervention team successfully milled 1,050 ft (320 m) of 9 ⅝-in. casing with the same pilot mill. After the casing was removed, the well was sidetracked by drilling out below the 13 ⅜-in. casing shoe. Due to the multiple cuts made in the casing string, milling operations were interrupted when short casing sections would become free and start spinning. Conventional fishing operations were used to pull the free section of pipe and milling operations could then resume. Several runs with the same milling assembly and pilot mill were made to achieve the planned depth of 1,050 ft (320 m). When the operation was completed, the mill showed a 65% wear.

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Challenges & Results


  • Barite settlement and cement between strings
  • Multile conventional cut-and-pull methods yielded limited success


  • Used robust METAL MUNCHER cutting technology for better assurance and efficiency
  • Increased footage/trip rate
  • Reduced NPT and increased milling bottomhole assembly longevity
  • Provided customer accurate real-time data during operation, allowing more precise decisions and driving efficiency